The first two are:

1.When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.

2.The only way of discovering the limits of the possible is to venture a little way past them into the impossible.

Arthur C. Clarke, the famed sci-fi author who penned these laws, is probably best known for co-authoring the screenplay to 2001: A Space Odyssee